node app.js 出现bug

[wappoint]

module.js:440
throw err;
^

Error: Cannot find module 'debug'
at Function.Module._resolveFilename (module.js:438:15)
at Function.Module._load (module.js:386:25)
at Module.require (module.js:466:17)
at require (internal/module.js:20:19)
at Module._compile (module.js:541:32)
at Object.Module._extensions..js (module.js:550:10)
at Module.load (module.js:456:32)
at tryModuleLoad (module.js:415:12)
at Function.Module._load (module.js:407:3)